Abstract: A non-intrusive finite element method for the reliability analysis of deformation for underground rock caverns is proposed. First, the polynomial chaos expansion is introduced. The software SIGMA/W is selected to perform the deterministic FEM analysis. Thereafter, a procedure for the interface between stochastic analysis module and software SIGMA/W is presented, and a flowchart is provided as well. The non-intrusive finite element method means there is no need for user-intervention during the calculation of the deterministic finite element code while the normal stochastic finite element methods always do. This is of practical advantage that realistic probabilistic analyses become possible for the practitioners. The computational efficiency of the proposed method is significantly higher than that of the traditional Monte Carlo simulation. It can serve as an alternate method for the reliability analysis of complex geotechnical problems. The liner supporting can improve the reliability of the underground rock caverns effectively. The sensitivity results indicate that the elastic modulus is the most significant random variable, whereas the unit weight almost has no influence on the reliability results. Therefore, to improve the reliability of the underground rock caverns effectively, a detailed geological investigation should be conducted to reduce the uncertainty in the elastic modulus of rock mass.